You can post it here.

Tell me your opinion.

They do it out of the slight errors of their opponents. The only reason they can turn thte tables is their opponents errors. A perfect machine would beat Fritz on its slight errors.

For the original topic, it doesn't really matter. You just have to be prepared for all openings. That's what matters.

I never found the time to learn a great multitude of openings. I try to stick with two openings for white and two for black. I believe that a person that knows a multitude of variations of just a few openings (having the time to learn them and the memory to retain them) will be a very strong player. I have obviously not achieved that as yet. :(

I never said anything against what you're doing. I'm just saying that there's a breaking point.

Ideally, you should have limited variety in your repertoire.  A friend of mine and I that have known each other for 20 years have opposite problems.  He has played the King's Indian and Accelerated Dragon (2...Nc6, Not Hyper) for ever and a day while I have played every sound opening under the sun not named the London System (I refuse to pay any respect to such a lazy man's good for nothing but a draw opening - The Colle Koltanowski is lightyears better than the London System).

Here's what I suggest:

White - Play one first move and deviate within.  For example, if you play 1.e4, you might play the Ruy Lopez as your main weapon against 1...e5 with an occasional dusting of 3.Bc4, the Scotch, or the Four Knights.  Against the French, you might normally play the French, but also occasionally play something like 3.Nc3.

Black - Minimum of 2, Maximum of 3 defenses against 1.e4 and same thing against 1.d4.  Two completely different Open Sicilians count as two different openings.  For example, I play the Sicilian Najdorf and Sicilian Taimanov against 1.e4.  Against 1.d4, lately I've been looking at the King's Indian, Old Indian, and QGD.

First and foremost, do not select openings at random, and secondly, do not try to force the same pawn structure in every game, meaning playing the KID does not make the Pirc a good idea.  They are vastly different openings.

You want diversity in your game.  It keeps your mind fresh.  Speaking from experience of being a former French player for 10 years straight, all White has to do is deviate the move order, and you get suckered into playing "normal moves" because that's all you've played for 10 years straight, and you just assume a transposition the following move, and BAM you are dead! 

Compare chess openings to a restaurant.  You live on a desert island and it has one restaurant with 100 entrees on the menu.  30 breakfast items, 30 lunch items, and 40 dinner items, but all 100 items are served 24/7.  Are you going to order item number 59 on the menu 3 times a day, 7 days a week, 365 days a year?  I don't about you, but as much as I love pizza, I couldn't eat pizza 1095 times a year!

The same thing goes for your chess game.  Don't try to play the same system over and over and over again.  Your play will get stale, you'll be playing out of habit, and not actually analyzing the position in front of you, and hence getting no better at the game!

I don't think there's such a thing as an ideal repertoire. 

In creating a repertoire, the first thing to consider is one's goals in chess. If you don't plan to become a +2000 player, play anything you like. If your goal is to become a GM, then your choices are much more limted. Here's a link to a great article on the topic by IM Greg Shahade. Yeah, I've posted this link before:

http://www.uschess.org/content/view/11634/675

I assure you that you don't have any opening figured out to move 16.  You might memorize the "main line" to move 16.  I know some lines of the Classical King's Indian into the 20s, or the Semi-Slav Botvinnik Variation, the Queen Sac line on move 21 I could play at least thru the mid-twenties in little to no time.  That does NOT mean that I can play 25 moves rapid fire of any variation and all legal deviations by White in the Semi-Slav Defense.

1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.Be2 e5 7.O-O Nc6 8.d5 Ne7 9.a3

Ok, what's your move?  Let's hear it, rapid fire, since you have everything memorized thru move 16!

1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 O-O 6.Be2 e5 7.O-O Nc6 8.d5 Ne7 9.a3

I know my blitz response, but you didn't ask me.

Added: I should mention that I don't have this position in my repertoire though. 

I always play Two Openings every time 

Italian or Ponzaini As white.

BettorOffSingle wrote:

I've played a singular repertoire since 1987, only recently ditching it for the "Chess960" approach of taking the game out of book at all costs.

The latter approach is easier since you're guaranteed a middlegame, but the quality of that middlegame will be much lower.  I do find that I play the opening very well on instinct so it's funny watching people not refute the bad lines I play (see the Reverse Ponz).

Since my coach is Fritz, I figure I should be able to learn how to crush players from lost positions, even -2.50 or more like the machines do.  If they can do it, I want to learn how.

WE ARE TALKING ABOUT 
 

Should we always play the same opening every time? Or different every time?

I think the opening systems are like a mini-game. If you win the mini game you get an edge, sometimes even a win.

So deciding what openings you play (and therefore which ones your opponent can amd can't play) is part of that game. If you get out-booked then the penalty is you have to start playing chess and your opponent may have a few perfect moves or even traps to throw at you before he has to even think.

But it's still a game. You study this or that? This is popular, and this is tricky, and so on. So to answer your question, playing a different opening every time, you are just conceding the mini-game every game.

Maybe you will be putting all your efforts into playing real chess, then, and in the end you grow more from that and this is harder to do. But I think it depends how you prep openings. Some ways of studying openings may strengthen your actual chess skills at the same time, but others won't.

This is an old thread but an important topic.

I think the best is to have two openings as white, that you can alternate between, like the London and the Reti, or 1e4 and 1b3, or 1f4, and two openings as black both against 1e4 and 1d4 (you can play against 1c4 and 1Nf3 and even 1f4 and 1b3 one of the systems you use against 1d4 like the QGD, or the King's Indian, for example).

In my case, I'm playing:

As white London and 1Nf3 trying to fianchetto both bishops

As black; Sicilian and French (but lines that are not very sharp, like the Rubinstein French and the Kalashnikov Sicilian); Bogo, Nimzo or QGD (I use the QGD formation against other openings too).

These systems and lines are nice because they avoid sharp lines that require much memorization. They can be played more around ideas and plans and not particular moves.

Also, having two options allows some variety according to your mood, opponent, etc.

This is true in correspondence chess and in +2700 OTB chess. Below that, there are quite a few titled players who have "killer repertoires". The theoretically correct answer often obscures the correct practical answer. 

A killer repertoire is only truly effective if you devote a tremendous amount of time and energy into creating your own theory of the opening. The simplest way to create a really strong repertoire is to model your game after a strong, but not elite GM. Players such as Dreev, Gawain Jones, and others play relatively narrow repertoires and score quite a few nice victories. 

Here, could disagreement arise from different interpretations of "killer repertoire"?

You should develop an opening repertoire, get good at it and stick to it.  You can't be good at everything.  Play a number of openings to find out what you are most comfortable in and go from there; it will be different for every player.

As an avid chess fanatic, I have only a few openings that I am really familiar with. If the opponent deviates from these lines, I just go along and play based on what my instinct says and how I understand the position. Maybe due to my age, I am not as passionate and daring on the chessboard, oftentimes, I find myself on the defensive side rather than being the attacker unlike in the early years of my playing. Sometimes I am surprised at the opening my opponent uses, but by being careful one can avoid mistakes and in the middle game everything is even.

"... If you want to play chess competitively, then you must develop an opening repertoire. ..." - GM Patrick Wolff (1997)

Eric Rosen seems to win a hell of a lot with the London for a "lazy man's draw opening".

My method has always been to stick with an opening till I get fed up with it, then move on to something else. Only now, after 15 years of club chess, am I starting to think I've almost reached a permanent repertoire. I do occasionally change it against specific players, to take them out of their comfort zone, but as that usually takes me out of mine, I'm not sure it's the best approach.